Adjustable steering mechanism



J. F; zlsKAL ADJUSTABLE STEERING MECHANISM July 19, 1960 Filed' Jan. 19, 1959 July 19, 1960 J. F. zlsKAL Y ADJUSTABLE STEERING MECHANISM 4 Sheets-Sheet 2 Filed Jan. 19, 1959 July 19, 1960 J. F. zvlsKAL 2,945,395

ADJUSTABLE STEERING MECHANISM 4 Sheets-Sheet 3 Filed Jan. 19, 1959 ,Zzz n for.' @bare/vh F Zz'sal July 19, 1960 J. F. zlsKAL A 2,945,395

` ADJUSTABLE STEERING MECHANISM Filed Jan. 19, 1959 4 Sheets-Sheet 4 FUE-5. 22 86 MCD'M @fffd' Unite ADJUSTABLE STEERING MECHANISM Filed Jan. 19, 1959, Ser. No. 787,435

9 Claims. (Cl. 74499) This invention relates to vehicle steering mechanisms and is particularly concerned with means for compensating for wear or correcting for dimensional inaccuracies between the drive-transmitting portions of such mechanisms.

In certain types of vehicles, particularly tractors utilized for farming operations, it is common practise to provide the vehicle with what is generally termed tricycle steering, i.e., a steering arrangement wherein a single or two closely spaced steerable wheels centrally positioned at the front end of the vehicle are mounted on the lower end of a vertically extending shaft or rotatable column that, in turn, is connected for control purposes through suitable motion-transmitting mechanism to an operators steering Wheel. Usually in this type steering mechanism the rotative motion -given to the control wheel by the operator is transmitted by way of a shaft, rod, or flexible linkage to a drive-transmitting means such as a worm or rack and pinion gear device which, in turn, transmits such motion to the upper end of the vertical shaft that carries the steerable front wheels and thereby effects the turning movement desired. Because of the extensive use to which such drive means, and particularly the worm or rack and pinion gear device, is subjected, by virtue of almost constant movement from one direction to another, the wear on the engaging portions of these elements becomes appreciable and must be compensated for in order to continue providing accurate steering control for the vehicle. Sometimes, too, manufacturing tolerances for dimensions are not as well maintained as they should be and the resultant inaccuracies in dimensions of the various elements, particularly the mesh tit of gears, in the mechanisms are such as to require some compensation or `correction in the assembled mechanism in order to provide the precise steering control desired.

In the past a great variety of means and methods have been proposed for effecting the adjustment desired beatent tween the gear elements of such mechanism in order to compensate for improper gear meshing, resulting either from wear or inaccurate dimensional factors, and thus be able to maintain accurate control of the steering in the associated vehicles. erally understood, most of the devices and methods `as have heretofore been proposed have not, for one reason or another, been entirely satisfactory. Some of these prior arrangements were cumbersome or expensive to fabricate, while others were not readily adaptable to use with power as well as manual steering mechanisms, and many, of course, failed to provide for improvement of the mesh fit of the gears when such. misalignment was the result of manufacturing inaccuracies.

It is a primary feature of the present invention, therefore, to provide a simple, improved, easily actuated and elfective adjustable means for improving the driving rela- Unfortunately, however, as is gentionship between engaging drive elements in a vehicle steering mechanism.

An important object is to provide in a manually or power operated steering mechanism a wear compensatorV ice vmeans applicable to the rack and pinion drive-transmitting gears thereof.

A more specific object is to provide a vehicle steering mechanism having engaging gears enclosed within a casing and wherein a sleeve-like member, fashioned With the inner and outer surfaces thereof eccentrically disposed with respect to one another, is rotatably interposed -between the engaging gears and the casing and which member upon rotation is operative to vary the distance between the respective rotative axes of said engaging gears.

Another object, generally, is to provide a vehicle steering mechanism wherein simplified and positive acting means is operative to vary in infinitely variable increments the distance between the respective rotative axes of operatively engaging driving and driven gears therewithin.

A further object is to provide, in a steering mechanism readily adaptable for manual or power operation, a unique and simplified means for adjusting one of the two gears in an engaging gear unit operative therewithin in order to compensate for wear or an improper meshing t of the gears in such operatively engaging relationship.

A still further object is to provide a novel, inexpensively fabricated and easily operated mechanism to facilitate the adjustment of the spacing between the rotative axes of gears in meshing engagement in order to compensate for wear or an improper mesh t of said gears.

The foregoing and other objects and advantages are lattained by the present invention, various novel features of which will be apparent from the description herein and the accompanying drawings disclosing one preferred` embodiment of the invention, and will be more particularly pointed out in the appended claims.

Fig. l is a side elevational view, with the wheels nearest the viewer removed, of a tractor in which the present invention has been incorporated, and shown with portions thereof broken away to better illustrate certain details.

Fig. 2 is a horizontal sectional view, in enlarged detail, taken on line 2-2 of Fig. l, showing the structural details of the proposed steering mechanism drive unit.

Fig. 3 is an end elevational view of the proposed steering mechanism unit.

Fig. 4 is a longitudinal and vertical sectional view, in enlarged detail, of the eccentric adjustment sleeve that forms an important part of the present invention.

Pig. 5 is an end elevational view of the eccentrically surfaced adjusting sleeve shown in Fig. 4.

Fig. 6 is a partial vertical sectional view, in enlarged detail, taken on line 6--6 of Fig. 2, showing the details of the mounting and support components of the present invention.

Fig. 7 is a partial vertical sectional view, in enlarged detail, taken generally along the line 7-7 of Fig. 2.

Referring now to the drawings, it will be noted that the tractor vehicle which has been selected for illustrating one preferred form or embodiment of the present invention, and designated generally by the reference character 10, is of conventional design, and includes a longitudinally extending frame or chassis 11, a steerable front wheel assembly 12, and a pair of spaced rear traction wheels 13 (only one of which is shown) driven by means of a driving engine 14 connectable thereto through a conventional change-speed transmission and associated differential or iinal drive unit, indicated in its entirety by the numeral 15. Other components and details, illustrated only to show their general relationship to the vehicle, have not been designated with reference numerals inasmuch as such details are not essential t0 3 the inventive 'concepts hereof and to do so might tend to make the 'drawings unnecessarily complex.

The steerable front wheel assembly illustrated herein is of the well known dirigible or .'tricycle. type that utilizes `a 'pair of 'slightly spaced inwardly inclinedor camb'ered wheels (only one of which .is shown) Amounted `ona "suitable unitary operated support means,.although the'use of a single steerable front wheel is'also envisaged asbeing well within the scope of the teachings'and concepts of the present invention.

Each of the steerable wheels 16 'may be suitably mounted, by conventional bearing and lock-nut retainer means (not shown), on oppositely extending horizontal -spindles or stud shafts, such as shownV at 17, carried by a vertically and downwardly depending bracketorrpost like member 18. A flange 19 at the upper end of said 'steering post is fastened by suitable ,bolt .or capscrew means, such as 20, to a similarly shaped flange 21 affixed to one end of a vertically extending rod or gear shaft 22 which is journalled, by the spaced bearings 23 and .24, carried in a stepped opening 25 in a bolster portion'26 of the vehicle chassis 11, and a pinion gear 27 affixed for rotation with said gear shaft is disposed intermediate said spaced bearings. kBec-anse of space limitations it is preferred that the pinion gear 27 be fashioned as an integral part of shaft 22, but it is understood that it could be separately fashioned and suitably aflxed thereto with- .out deviating from any teachings hereof.

The bolster member 26, preferably, isfashioned .asa unitary structure that extends between thelforward side rails or channel portions 28 of the vehicle chassis or frame 11, and is suitably secured thereto such as by the .bolt means 29, and functions -as atransverse structural member for the forward portion of .the frame as well as providing a housing or casing portion 30 for Ythe steering :drive-.transmitting mechanism. Extendinginwardly from the rearward edge of the .housing portion 30 of said bolster is a cylindrical recess 31 that delimits achamber .adapted to receive in .housing or casing relationship certain components of the proposed steeringmechanism as will presently be described. Mounted forlimited rotation within said cylindrical recess is an elongated sleeve member 32 having a piston-like plunger 33, with a gear rack 34 formed along one side thereof, that is positioned within said sleeve and which, in turn, is disposed for Yslidable movementlongitudinally within thesleeve. This piston and rack assembly may be termed a driving member. The gear rack 34 meshesY with .the piniongear 27, which may be termed ya driven member, mounted on gear shaft 22, which extends .through openings 25.and.35 in the bolster housing portion30 and side wall of. sleeve 3 2, respectively, and thus, in eect, operatively or drivingly connects said gear rack member to the steerable wheel assembly. The piston or plunger 33 is fashionedwith a centrally disposed and longitudinally extending axially stepped recess 36 that is adapted to accommodate one end of a threaded shaft such as 37. An enlarged portion 38, of said recess, receives. a traveling nut member -39 having a threaded opening therethrough with threads 40 formed therein for matingly receiving the convolutions of a worm gear or the threads 41 providedon shaft 37.l The traveling nut 39 has a recessed shoulder portion 42 at one end thereof that seatingly accommodates a retainer or end plate member 43, atixed, by suitable securing means such as the capscrews 44, to the.end surface of piston 33 and which, as thus disposed, functions to 'retain said traveling nut against axial displacement relative to said pisto A threaded locking pin or'stud 45 positioned in a threaded opening 46 in the wall of .piston 33 has a reduced-section end portion vt7 thereon that projects or extends into an interlocking opening 48 in the outer surface of nut member-39, and said pin when thus interlocked serves to prevent independent rotation of said nut with respect to said piston.

-The Opposite or outwardly extending end of the 4 threaded shaft 37 is journalled in a bearing 49, mounted Yin'a'cap or covermember 50, with`suitable liquid'seals 51 and 52 positioned on either side of said bearing for sealing said shaft against the seepage of liquid therealong. The cap 50 is closely positioned against a collar or ring-like member 53 which, in turn, is positioned against the outer surface' of Laflange 54, on sleeve 32, whilecapscrews, such as Vshown at 55 (Fig. 3), serve to securely affix said cap,collar and'sleeve'flange members together and to .the.housing.3t). VAconventional liquid seal 56, in Aa recess 57r-in the housing 30 facing one side of ange 54, and anotherseal'tSS, Vina recess59 on the opposite side of. said ange, provide suitable liquid sealing means around theedges'of the'flanges as will be well understood. It willbeappreciated that, if desired, the cam member 50 and collar 53 could be fashioned as a unitary member without deviating from any of the teachings of theA present invention.,

A collar or annular .rim 6i! carried by the shaft 37 provides an abutment for oneside of a thrust bearing assembly or reactor means, indicated .generally by the reference numeral 61, positioned around said shaft and secured against relative axial movement therealong by means of a lock-nut 62 threadably mounted on said shaft. Said thrust bearing or reactor-assembly includes a thrust plate or reactor member 63 centrally disposed between .a pair of axially spaced back-up plate members 64 and 64a with suitable radial needle bearings 65 and 65a operatively positioned between the respective facing surfaces of said three plate members. A combination -washer and lockanut 'retainer 66 is positioned between the end or backup plate 64a and. the lock-nut 62 for .purposes which are well understood. The centralv plate reactor member 63, being of larger diameter than the adjacent plates 64 `andf64a, hasa peripheral edge portion that extends outwardly beyond the edges of said .adjacent back-up plates and into an annular groove 67 delimited by recess 68 in ring 53 and the adjoiningfacing surface of hood or cam member 50. An additional `recessv69 may be provided in the vicinity of recess 68, in ring member 53, for receiving a conventional liquid seal 70. It will be readily understood now that the thrust bearing assembly 61 .provides `means for receiving and counteracting any axial thrust of the shaft 37 so as to prevent axial displacement ofsaid shaft as a result of forces transmitted ythereto by operation of the engaging rack and pini-on gears 34and 27 On lthe outer end of worm.shaft.37 there is slidably mounted for. rotation therewith, by. suitable splining such as indicated at 71, a universal joint coupling 72 the oppositeendof which is fastened to a .first intermediate shaft 73 and saidlattershaftis journalled by means of 'a spherical bearing 74 .mounted in bracket 75, in turn, aflixedto .the vtractor frame :11, bysuitable securing meansv such as .the capscrews 76. Asecond .universal joint 77 .connects the rst Aintermediate shaft 73 to a .second intermedateshaft 78 which isconnected by a .universal joint 79 Yto a steering column shaft 80 the .loppositeend of whichmay have an operators steering wheel 81 suitably secured thereto. A 'bearing bracket .82,.afxed to the .-chassis. 11 by suitable-securing means such as the capscrews 83, suitably journals the shaft 80 .and thus provides means for rotatably supporting the latter ,shaft on said chassis.

Theuppertendof opening 25 y(Eig. Y6),terminating in the upperparttof housing 3i) proximate the end of the gear shaft .22, provides a means which maybe used for lubricating andi like purposes, 'while a cover member 84 positionable over said opening may be suitably detachably secured thereto by fastening .means-such as the capscrews v85. A threadedaccess .plug 864 may berprovided in said .cap tol permit the introduction vof lubricatingfluid without .having to remove the cap.

The sleeve 32, which forms an important -partofthe present invention, is. generally elongated andthe exterior dimensions thereof `4substantially conform 'with .the .in-

'5). The flange l54, on one end of said sleeve, is provided with a plurality of peripherally extending and spaced notch-like recesses 89 dimensioned so as to accommodate the shanks of the respective capscrew fastening means 55 (Fig. 3) utilized for detachably affixing sleeve llange 54, collar 53 and end cover 50 to the vhousing 30. A pair of diametrically spaced ears or lugs 90, 90a, extending radially outwardly from the periphery of said flange, provide means for manually rotating the sleeve 32 within the cylindrical recess 31 in order to effect the adjustment desired as will presently be more fully explained. The opening 35 in the wall of said sleeve is dimensioned so as to permit limited rotation of the sleeve and still accommodate gear shaft 22 and associated pinion gear 27 as they pass therethrough and into engagement with the gear rack 34.

When the operator turns the wheel 81 to the right or left, according to the direction in which it is desired to steer the vehicle, the rotative motion thereof is transmitted by way of the connecting and converting yieldable means embracing interconnected steering column shaft 80, intermediate shafts 78 and 73 and threaded shaft 37, to the piston or driving member 33, whereupon the worm threads 41 and the cooperating threads 40 in nut 39 react against one another, but, since the thrust or reactor bearing assembly 61 prevents said threaded shaft from moving axially, and reaction set up between said worm and threaded nut, as a result of the rotation of said threaded shaft, will cause the nut to move axially carrying with it the interlocked piston or plunger 33', thus converting the rotary motion of the wheel 81 to a reciprocatory motion in the piston gear rack 34. As the piston moves axially the gear rack 34 thereon being in meshnwith the pinion gear member 27 will cause the rotation of this driven pinion and such motion, in turn, will rotate the gear shaft 22 and the attached steering post 18 to steer or turn the vehicle in the direction desired, thereby converting the reciprocatory motion of the driving piston gear rack to rotary motion in the steerable wheel assembly.

Now, in order to improve the meshing relationship so'as to compensate for wear or correct for improper meshing t of the engaging surfaces of rack 34 and pinion 27 the present invention contemplates providing Ymeans for moving or shifting the respective longitudinal axis of one of these gears toward or away, as necessity dictates, from the other, and such displacement is accomplished with the aid of the eccentrically `surfaced adjustable mounting sleeve 32. In the instant illustration, since the axis of the pinion gear is relatively fixed, the axis of the gear rack is the one that is adapted for movement. When it is desired to eiect the necessary adjust,-

yment or displacement of the latter axis the fastening cap- -new parallely displaced axis. By thus shifting the rotative axis of the gear rack it is possible to bring the meshing surfaces of said rack and pinion into better and more complete meshing relationship, thereby correcting or com- ;pensating forwear or for any misalignment error, lbejteri'or 'dimensionsv of the cylindrical recess 31, in liousl ing 30, so that said sleeve may be rotatably positioned -therewithin The cylindrical exterior surface 87 of said -6 cause' of manufacturing 'or other dimensional inaccuracies, thereof. A A

As the longitudinal axis of the threaded shaft 37 is thus displaced parallel unto itself the slidably attached universal jointcoupling 72 is also transversely displaced by the same amount as the shafts axis and this limited movement produces a concomitant small axial movement of said coupling. However, since coupling 72 is splined to shaft 37 it will be appreciated that this small axial movement may easily be accommodated without hindering the rotative movement of the adjustable sleeve 32. As one aid to facilitate the accommodation of the axial and radial displacement of coupling 72, however, the opposite end of shaft 73 is journalled in the spherical bearing 74 thereby permitting connecting shaft 73 a reasonable leeway in the axial and transverse movement of the end attached to coupling 72. VIn the event additional leeway for axial movement of the shaft 73 is desired such may be obtained by way of the universal couplings 77 and 79 which`connect the second intermediate shaft 78, respectively, to the shafts 73 and 80 thereby permitting a reasonable amount of movement for shaft 73.

As thus arranged the means that drvingly or operatively connects the operators wheel 81 with piston driving member 33 will be seen to be a yieldable or flexible connecting means and it fwill be appreciated that other well-known or conventional connecting means may be used for such purpose while the one selected for illustration herein is only one preferred adaptation andhence the invention should not be limited thereto. A Bowden or flexible wire type of control cable, Which is well known in the art, could conceivably be used in lieu of the linkage illustrated without deviating from the teachings hereof. Since the amount of transverse movement or axis displacement effected by the adjusting sleeve 32 is-quite small relatively speaking it would be possible to use the present device without a yieldable connection between the piston and the operators wheel, but the preferred application, Iwhich provides a smoother and more easily manipulated device, envisages the use of a yieldable operative connection therebetween. i

Although the present invention has been illustrated as applied to a manually operated vehicle steering mechanism, it is equally applicable to a power assist mechanism without deviating from the teachings hereof. For instance, by replacing the thrust bearing assembly 61 with a well known type of valve actuating device, such as is shown in my copending U.S. patent application, Serial No. 673,086, led July 19, 1957, and then installing rings on the piston 33 and suitable oil seals in the cylindrical recess 31, the mechanism would be ready for connection into a hydraulic system, for use as a power-operated mechanism, and' the operation of the adjustable eccentric mounting sleeve, to improve the meshing relationship so as to compensate for wear or other inaccuracies of the 'rack and pinion gears, would be identical with that previously described.

lt should now be apparent that a novel means for adjusting -gears in a steering mechanism to improve their meshing relationship so as to compensate for wear orcorrect for dimensional inaccuracies therein has been shown and described, and it is to be understood that changes may be made in the construction without departing from the spirit of the invention or the scope thereof as defined in the appended claims.

What is claimed is:

1. In a vehicle steering mechanism adapted for connection at one end to an operators control wheel and at the other end thereof to a vehicle steerable wheel assembly, the combination, comprising: a reciprocable driving member; motion transmitting means connectable between said reciprocable driving member and the operators control wheel and operable for converting rotary motion of the operators wheel to reciprocatory movementrof .the "drivingimembeni a shaft :connectable. at one end to the steerable wheel assembly and having adriven y:member mountedithereon Vand constrained .for'rotation therewith; said :driven member being disposed in Vdriving :relationwith said reciprocable.driving-:member and operable for converting reCiProcatoryf motion of the driving member to rotary motion for steering the steerable wheel -rassemblyyfand eccentric means engageable -with said reciprocable driving member and adjustablefor varying tion atone `end toan operators control wheel and at the other end thereof to a vehicle steerable -wheel assem- ..bly, the combination; comprising: a housing vhaving a .recess-extending inwardly from an end thereof; a gear .rack'member slidably positioned within said recess; means connecting said gear rack member -with the operators control wheel and operable for sliding said gear rack within said recess in response to turning of the operators control Wheel; means connectable at one end to the steerable Wheel assembly andincluding a shaft with a pinion gear mounted on the end thereof and constrained for rotation therewith and disposed in meshing engagement with said gear rack member, and operable for converting the sliding motionl of said gear rack member into rotary motion for turning .the steerable wheel assembly; rotatable means including .a hollow member rotatable on an 4axis parallel to the axisalong which said gearrackmem- .-ber slides and interposed between said `gear rack member and said housing and reactive therebetween upon rotation for .displacing the axis along which saidrgear rack slides land selectively moving it toward or away from the axis upon which said piniongearrotates so'as to obtain im- .proved meshing engagement betweensaid gears.

.3. .In a vehiclesteering mechanism adapted for interconnection bet-weenan operators control wheel and a .steerable wheel assembly, thecombination, comprising:

a .housing supported by the vehicle and having a cylindrical recess extending inwardly from an end thereof;

.a driving member slidably positioned within said recess;

means operatively connecting said .driving member with theoperators control wheel and .operable for slidably moving said driving member ywithin said recess in response .to va turning of the operators control wheel; .means .drivingly connectable between the vehicle steerable wheelassemblyand said driving member,.including .ashaft .having a driven member mounted thereon and constrained for 'rotation therewithand disposed in drivy.ing relation withsaid driving member, .and operablefor converting. the sliding motion of said driving member-into A.arotary motion that turns the steerable'wheel assembly; .a rotatable sleeve .interposed between saiddriving mem` .ber and-said housing; said sleeve being fashioned with the outersurface thereof eccentrically disposed Withrespect to the inner surface so that upon rotation of the .sleeve said Isurfaces are reactive between said housing and said driving member for varying the distance'be-k tween the axis along which said driving member slides .and the axis .about which said driven member rotates in orderA to improve the driving relationship therebetween.

lLina-vehicle steering mechanismadapted for interconnectionbetween an operators control wheel and a steerable wheel assembly, the combination, comprising: a housing supported by the vehicle and havingacylindrical recess extending inwardly from .an end thereof; agear rack memberslidably positioned within said recess; means operatively .connecting said gear raclomember with the operators control wheel and` operable for slidably movingsaidgear rack within said .recess inresponse to a turning of the operators control wheel; means operatively '.connectable between thefvehicle steerable wheel assembly and saidgrgear rack member; including .a .-.shaftL having L-.a

piniongear mounted :thereon and constrained [for rotaltion therewith vand disposed .in meshingrelationY with said gear: rack, `and operable for `converting therslidingzmotion of said gear rack member intoa rotarymotionthat turns thesteerable Awheel assembly; a longitudinally: extending sleeve interposed between vsaid gear racknnem- .ber and said housing and disposed for limited rotation in both directions about Aa longitudinal axis; said sleeve lhaving the outer surface thereof circumscribedabout a longitudinal axis which coincides with the longitudinal axis of Said cylindrical recess while the inner surface of said sleeve is circumscribed about a longitudinal axis parallelly displaced from the axis of `said outer sumfaceso that upon .rotation of the sleeve the axis of said inner surface is displaced Aand selectively moved toward or -away from -means operatively connecting said gear rack member with the operators control `wheel and operable for slidably. moving saidfgear rack within said recess in response lto a turning of the operators control wheel; meansoperatively connectable between the vehicle steerable wheel assembly and said gearrack member, including a shaft having a pinion gear mounted thereon andconstraned for rotation therewith and disposed in meshing relation with said gear rack, and operable for converting the sliding motion of said gear ,rack member into a rotary motion that turns the steerable wheel assembly; a longitudinally extending sleeve interposed between said gear rack member and said housing and disposed for limited rotative movement about the longitudinal axis thereof; .ange means on one end of said sleeve engageable in abutting relation with said housing; fastening means cooperative between said housing and said ange for xedly positioning said sleeve against axial and rotative displacement with respect to said housing; said sleeve being fashioned on the longitudinal axis thereofwith fthe outer surface ..eccentrically `disposed with respect to t-he innersurface so that upon rotation of said sleeve said surfaces are reactive .between saidhousing and said gear rack member for varying the :distance between the longitudinal axis of said gear rack member and the rotative axis of said pinion gear in order to obtain optimum meshing engagetment of said gears.

6. In a vehiclesteering'mechanism adaptedfor interconnection .between an operators control wheel and a steerable wheel assembly, the combination, comprising: a housing adapted rfor atlix-ment to the vehicle and having a cylindrical recess extending inwardly from an end thereof; a longitudinally extending sleeve disposed for limited rotative movement within said recess; a piston slidably positioned within said recess; means operatively connecting said piston with the operators control wheel and operative for slidably moving said piston Within said recess in response to a turning of the operators control Wheel; said piston having a longitudinally extending gear rack provided thereon; means including a shaft having a pinion thereon and constrained for rotation therewith and disposedin meshing relation with said gear rack operatively connected between the steerable wheel assembly v'and said gear'rack and operative for converting vthe sliding motion of said gear rack into a rotary motion that turns the steerable wheel assembly; said sleeve having an opening therein to accommodate passage of said shaft and pinion; a radially extending iiange on one end of said Asleeve engageable inrabutting relation with said housing; ksaid flange having a pluralityof vcircumferentially vlextending and peripherally lspaced notch-like recesses therein; detachablefastening .means carried fbyxsaid i. housing par J and cooperative with the recesses in said flange for positionlng said sleeve against axial and rotative movement with respect to said housing; said sleeve being fashioned with the outer surface eccentrically disposed on the longitudinal axis thereof `with respec-t to the inner surface of the sleeve so that upon rotation of the sleeve said sleeve reacts between said housing and said piston to cause a parallel displacement of the longitudinal axis of said piston and thereby effecting a variation in the distance between the longitudinal axis of said gear rack and the rotative axis of said pinion gear.

7. In a vehicle steering mechanism adapted for interconnecting between an operators control wheel and a steerable wheel assembly, the combination, comprising: a housing adapted for aftixment to the vehicle and having a cylindrical recess extending inwardly from an end thereof; a longitudinally extending sleeve disposed for limited rotative -movement within said recess; a piston slidably positioned within said recess; yieldable means operatively connecting said piston with the operators control wheel and operative for slidably moving said piston within said recess in response to a turning of the operators control wheel and yieldable to permit limited radial and axial displacement of portions thereof in the vicinity of the piston; said piston having a longitudinally extending gear rack provided thereon; means including a shaft having a pinion thereon and constrained for rotation therewith and disposed in meshing relation with said gear rack operatively connected between the steerable wheel assembly and said gear rack and operative for converting the sliding motion of said gear rack into a rotary motion that turns the steerable wheel assembly; said sleeve having an opening in the wall thereof dimensioned to accommodate said pinion gear and shaft during all of the related movements of the sleeve; a radially extending flan-ge on one end of said sleeve engageable in abutting relation with said housing; said flange having a plurality Iof lugs extending radially therefrom to facilitate manual rotation thereof; detachable means carried by said housing and cooperative with said flange for fastening said sleeve against movement relative to said housing; said sleeve being fashioned with the outer surface eccentrically disposed with respect to the inner surface thereof so that upon rotation of the sleeve said sleeve reacts between said housing and said piston to cause a parallel displacement of the longitudinal axis of said piston, thereby effecting a variation inthe distance between the longitudinal axis of said gear rack and the rotative axis of said pinion gear.

8. In a vehicle steering mechanism adapted for interconnection between an operators control wheel and a steerable wheel assembly, the combination, comprising: a housing adapted for aiiixment to the vehicle and having a cylindrical recess extending inwardly from an end thereof; a longitudinally extending sleeve disposed for limited rotative movement within said recess; a piston slidably positioned within said recess; yieldable connectingmeans operatively connecting said piston with the operators control wheel and operative for slidably moving said piston within said recess in response to rotation 'of the operators control wheel; said connecting means including a plurality of spaced llexible couplings one of which is mounted for slidable axial movement, and being disposed to permit small increments of transverse and axial displacement of the portion of said means near said piston; said piston having a longitudinally extending gear rack fashioned thereon; means operatively connectable between the vehicle steerable wheel assembly and said gear rack, including a shaft having a pinion gear constrained for rotation therewith and having said shaft disposed in a plane normal to the longitudinal axis of said gear rack and with said pinion gear disposed in meshing engagement with said 10 Y gear rack, and operative for converting the sliding motion imparted to said gear rack into a rotary motion that turns the steerable wheel assembly, said sleeve having an opening therein dimensioned to accommodate said pinion gear and shaft; a radially extending flange on one end of said sleeve engageable in abutting relation with said housing; said flange having a plurality of peripherally spaced and extending recesses therein; detachable means carried by said housing and cooperative with said recesses for fastening said sleeve against movement with respect to said housing; said sleeve being fashioned with the outer surface centered on a longitudinal axis parallelly displaced from the longitudinal axis about which the inner surface of said sleeve and said piston are centered sothat upon rotation of said sleeve about vits longitudinal axis said sleeve reacts between said housing and said piston to cause a parallel displacement of the longitudinal axis of said piston and incident thereto a variation in the distance between the longitudinal axis of the gear rack on said piston and the rotative axis of said pinion gear.

9. In a vehicle steering mechanism adapted for interconnection between an operators control wheel and a steerable wheel assembly, the combination, comprising: a housing adapted for aixment to the vehicle and having a cylindrical recess extending inwardly from an end thereof; a longitudinally extending sleeve disposed for limited rotative movement within said recess; a piston slidably positioned within said recess; connecting means operatively connecting said piston with the operators control wheel and operative for slidably moving said piston within said recess in response to rotation of the operators control wheel; said connecting means including a plurality of spaced flexible couplings disposed to permit small increl ments of transverse displacement of the portion of said means near said piston; said piston having a longitudinally extending gear rack fashioned thereon; means operatively connectable between the vehicle steerable wheel assembly and said gear rack, including a shaft having a pinion gear constrained Ifor rotation therewith and having said shaft disposed in a plane normal to the longitudinal axis of said gear rack and with said pinion gear disposed in meshing engagement with said gear rack, and operative for converting the sliding motion imparted to said gear rack into a rotary motion that turns the steerable wheel assembly; said sleeve having an opening therein dimensioned to accommodate `said pinion gear and shaft; a radially extending flange on one end of said sleeve engageable in abutting relation with said housing; said ange having a plurality of peripherally spaced and extending recesses therein; detachable means carried by said housing and cooperative with said recesses for fastening said sleeve against movement with respect to said housing; said sleeve being fashioned with the outer surface centered on a longitudinal axis parallelly displaced from the longitudinal axis about which the inner surface of said sleeve and said piston are centered so that upon rotation of said sleeve about its longitudinal axis said sleeve reacts between said housing and said piston to cause a parallel displacement of the longitudinal axis of said piston and incident thereto a variation in the distance between the longitudinal axis of the gear rack on said piston and the rotative axis of said pinion gear.

References Cited in thele of this patent UNITED STATES PATENTS 1,193,133 Flora Aug. l, 1916 2,068,679 Hokansson Jan. 26, 1937 2,784,611 Davis Mar. 12, 1957 FOREIGN PATENTS 455,844 Germany Feb. 10, 1928 

